Method of forming different voltage devices with high-k metal gate

Abstract

A method and apparatus are described for integrating high voltage (HV) transistor devices and medium voltage or dual gate oxide (DGO) transistor devices with low voltage (LV) core transistor devices on a single substrate, where each high voltage transistor device ( 160 ) includes a metal gate ( 124 ), an upper high-k gate dielectric layer ( 120 ), a middle gate dielectric layer ( 114 ) formed with a relatively lower high-k dual gate oxide layer, and a lower high voltage gate dielectric stack ( 108, 110 ) formed with one or more low-k gate oxide layers ( 22 ), where each DGO transistor device ( 161 ) includes a metal gate ( 124 ), an upper high-k gate dielectric layer ( 120 ), and a middle gate dielectric layer ( 114 ) formed with a relatively lower high-k dual gate oxide layer, and where each core transistor device ( 162 ) includes a metal gate ( 124 ), an upper high-k gate dielectric layer ( 120 ), and a base oxide layer ( 118 ) formed with one or more low-k gate oxide layers.

What is claimed is: 
     
       1. A method of forming a plurality of gate electrode structures on a shared substrate comprising:
 forming a first gate dielectric device in a first region of a semiconductor substrate for one or more first voltage level transistors, wherein the first gate dielectric device comprises a grown gate dielectric layer formed on the shared substrate, a deposited gate dielectric layer formed on the grown gate dielectric layer, a first high-k gate dielectric layer deposited on the deposited gate dielectric layer, and a second high-k gate dielectric layer deposited on the first high-k gate dielectric layer; 
 forming a second gate dielectric device in a second region of a semiconductor substrate for one or more second voltage level transistors, wherein the second gate dielectric device comprises the first high-k gate dielectric layer deposited on the shared substrate, and the second high-k gate dielectric layer deposited on the first high-k gate dielectric layer; 
 forming a third gate dielectric device in a third region of a semiconductor substrate for one or more third voltage level transistors, wherein the third gate dielectric device comprises a base gate dielectric layer grown on the third region of the shared substrate and a second high-k gate dielectric layer deposited on the base gate dielectric layer; 
 forming one or more gate conductor layers on the first, second, and third gate dielectric devices; and 
 selectively etching the gate conductor layers and the first, second, and third gate dielectric devices to form a plurality of gate electrode structures on the first, second, and third regions of the shared substrate; 
 where the first gate dielectric device has a combined thickness that is thicker than the second gate dielectric device, where the second gate dielectric device has a combined thickness that is thicker than the first gate dielectric device, and where the first voltage level is higher than the second voltage level which is higher than the third voltage level. 
 
     
     
       2. The method of  claim 1 , where the first high-k dielectric layer has a first dielectric constant value that is smaller than a second dielectric constant value for the second high-k dielectric layer. 
     
     
       3. The method of  claim 1 , further comprising epitaxially growing a compressive silicon germanium layer the second region of the semiconductor substrate and in a portion of the third region of the semiconductor substrate where PMOS transistors are formed prior to forming the second and third gate dielectric devices. 
     
     
       4. The method of  claim 1 , where forming the first gate dielectric device comprises:
 thermally growing a first oxide layer as the grown gate dielectric layer on at least the first region of the semiconductor substrate; 
 depositing a second oxide layer as the deposited gate dielectric layer on the first oxide layer over at least the first region of the semiconductor substrate; 
 depositing a dual gate oxide layer as the first high-k gate dielectric layer on the second oxide layer over at least the first region of the semiconductor substrate; and 
 depositing a hafnium oxide layer as the second high-k gate dielectric layer on the dual gate oxide layer over at least the first region of the semiconductor substrate. 
 
     
     
       5. The method of  claim 1 , where forming the second gate dielectric device comprises:
 depositing a dual gate oxide layer as the first high-k gate dielectric layer on at least the second region of the semiconductor substrate; and 
 depositing a hafnium oxide layer as the second high-k gate dielectric layer on the dual gate oxide layer over at least the second region of the semiconductor substrate. 
 
     
     
       6. The method of  claim 5 , where depositing the dual gate oxide layer comprises depositing a layer of HfxSil-xOy or HfxSil-xOyNz on at least the second region of the semiconductor substrate. 
     
     
       7. The method of  claim 1 , where forming the third gate dielectric device comprises:
 thermally growing a base oxide layer as the base gate dielectric layer on at least the third region of the semiconductor substrate; and 
 depositing a hafnium oxide layer as the second high-k gate dielectric layer on the base oxide layer over at least the third region of the semiconductor substrate. 
 
     
     
       8. The method of  claim 1 , where forming one or more gate conductor layers comprises:
 depositing one or more metal-based barrier layers on the first, second, and third gate dielectric devices; and 
 depositing a polysilicon layer on the one or more metal-based barrier layers to cover the first, second, and third regions. 
 
     
     
       9. The method of  claim 8 , where selectively etching the gate conductor layers and the first, second, and third gate dielectric devices comprises:
 forming a patterned etch mask on the polysilicon layer with one or more openings formed over the polysilicon layer and underlying one or more metal-based barrier layers and the underlying first, second, and third gate dielectric devices; and 
 selectively etching through the one or more openings in the patterned etch mask to remove exposed portions of the polysilicon layer and underlying one or more metal-based barrier layers and the underlying first, second, and third gate dielectric devices to form the plurality of gate electrode structures on the first, second, and third regions of the shared substrate. 
 
     
     
       10. The method of  claim 9 , further comprising forming a silicide layer on each of the plurality of patterned gate electrodes to form a plurality of patterned high-k metal gate electrodes. 
     
     
       11. The method of  claim 1 , where the steps of forming the first, second, and third gate dielectric devices use a single etch step to remove the grown gate dielectric layer, deposited gate dielectric layer, and first high-k gate dielectric layer from the third region of the semiconductor substrate before forming the base gate dielectric layer and second high-k gate dielectric layer.